remove

I just picked up my first USP9 Compact pistol today. I am trying to figure out what parts I would need to change it slightly. It is a PW Imports that Classic Arms sold in a few years ago. It is definitely a LEM trigger, but unlike any other LEM HK I have owned, it has an ambidextrous safety...

I am in process of installing a new trigger for my HK, and in order for it to function I have to remove the firing pin safety. I have successfully removed the rear pin...simply just tapping it, but the front pin doesn't move at all?? Can some of you bright minds tell me what I am doing wrong...